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c/r: prctl: drop VMA flags test on PR_SET_MM_ stack data assignment

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In commit b76437579d ("procfs: mark thread stack correctly in
proc/<pid>/maps") the stack allocated via clone() is marked in
/proc/<pid>/maps as [stack:%d] thus it might be out of the former
mm->start_stack/end_stack values (and even has some custom VMA flags
set).

So to be able to restore mm->start_stack/end_stack drop vma flags test,
but still require the underlying VMA to exist.

As always note this feature is under CONFIG_CHECKPOINT_RESTORE and
requires CAP_SYS_RESOURCE to be granted.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Cyrill Gorcunov 2012-06-07 14:21:12 -07:00 committed by Linus Torvalds
parent 300f786b26
commit 736f24d5e5
1 changed files with 0 additions and 14 deletions
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14
kernel/sys.c
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@ -1786,14 +1786,6 @@ SYSCALL_DEFINE1(umask, int, mask)
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static bool vma_flags_mismatch(struct vm_area_struct *vma,
unsigned long required,
unsigned long banned)
{
return (vma->vm_flags & required) != required ||
(vma->vm_flags & banned);
}
static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd)
{
struct vm_area_struct *vma;
@ -1931,12 +1923,6 @@ static int prctl_set_mm(int opt, unsigned long addr,
error = -EFAULT;
goto out;
}
#ifdef CONFIG_STACK_GROWSUP
if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSUP, 0))
#else
if (vma_flags_mismatch(vma, VM_READ | VM_WRITE | VM_GROWSDOWN, 0))
#endif
goto out;
if (opt == PR_SET_MM_START_STACK)
mm->start_stack = addr;
else if (opt == PR_SET_MM_ARG_START)